Wii Sports Resort - 30 million
NSMB Wii - 26 million
Wii Fit Plus - 20 million
Something that I think is worth noting is that all 3 of those games will have released over 3 years prior to the Wii U's projected launch. The casual market's changed a lot in 3 years. 3 years ago, I'd go to a public place and I'd see a large chunk of people playing Sodoku (or some other casual experience) on their DS. Just yesterday I was at a doctor's office, and half the waiting room (of about a dozen or so people) were browsing the internet or playing solitaire on their smart phones.
My point is that just because something sold exceptionally well to the casuals 3 years ago, that doesn't mean it will necessarily sell to that extent
now (especially with the economy only having gotten worse). Just observe how Wii hardware and software sales have plummeted in the last few years as the mobile gaming market has soared. 3 years ago, a program like Wii Fit would have seemed a useful way to track exercise. These days, my mother's phone has half a dozen Apps dedicated to exercise. The various mobile games stores have flooded the market with casual experiences, as well. Are these experiences as good as something Nintendo might make? No, but the casuals generally seem to consider them
"good enough" for their needs.
Maybe Nintendo's casual gamble will pay off again with these Wii U launch games, but I definitely wouldn't treat it as a "sure thing" at this point. Nintendo still has a lot to do between now and the launch to prove that the Wii U is a device that people who don't ordinarily follow games
need to buy. And considering right now they seem to have a continual problem convincing casuals that the Wii U is a
new console, I'd say they have their work cut out for them.